RESUMO
An 84 base pair sequence of the Streptococcus mutans virulence factor, known as dextranase, has been obtained from 10 individuals from the Bronze Age to the Modern Era in Europe and from before and after the colonization in America. Modern samples show four polymorphic sites that have not been found in the ancient samples studied so far. The nucleotide and haplotype diversity of this region have increased over time, which could be reflecting the footprint of a population expansion. While this segment has apparently evolved according to neutral evolution, we have been able to detect one site that is under positive selection pressure both in present and past populations. This study is a first step to study the evolution of this microorganism, analysed using direct evidence obtained from ancient remains.
Assuntos
Cárie Dentária/microbiologia , Dextranase/genética , Streptococcus mutans/genética , Sequência de Aminoácidos , Sequência de Bases , Haplótipos , História do Século XV , História do Século XX , História Antiga , História Medieval , Humanos , Dados de Sequência MolecularRESUMO
Las técnicas moleculares para recuperar DNA antiguo brindan la posibilidad de comparar la evolución molecular a través del tiempo, ya que constituye una herramienta para aclarar el diagnóstico de posibles enfermedades infecciosas del pasado. Aislar y secuenciar un fragmento de DNA de Streptococcus mutans fosilizado, considerado el principal agente infeccioso implicado en la formación de la placa bacteriana y el desarrollo de la caries dental, utilizando la reacción en cadena de polimerasa (PCR). La muestra estuvo conformada por caries y tártaro dental proveniente de dientes de diferentes colecciones de México, Barcelona e Islas Baleares. La metodología fue adaptada a las condiciones de conservación de este tipo de muestra para obtener DNA y los primers fueron específicos para la amplificación de un fragmento de 124 pb del gen de la Dextranasa del S. mutans. De las 24 muestras analizadas, 9 resultaron positivas para la amplificación y en 6 se lograron las secuencias correspondientes. Para la alineación de las secuencias obtenidas, se empleó la base de datos BLAST encontrándose una homología del 95% con el genoma del S. mutans UA159. Este estudio demuestra la primera evidencia de obtención de la secuencia de un fragmento de DNA de Streptococcus mutans recuperados a partir de caries y cálculo dental de restos humanos antiguos, presentando un 95% de homología con el DNA de S. mutans de la subespecie UA159 moderno
The molecular techniques for ancient DNA recovering, offers the possibility to compare the molecular evolution through time as these are tools which make clear possible infectious diseases from the ancient times Objective: To isolate and sequence fossilized Streptococcus mutans DNA fragments, considered the infectious agent involved with dental caries and plaque formation and development, by using the polymerase chain reaction (PCR). Dental caries and tartar samples of teeth collections from Mexico, Barcelona and Balearic Islands. The methodology was adapted to the conservation conditions of this type of DNA samples, and primers were specific to amplify a fragment of 124 bp of S. mutans dextranase gene. Results: 24 samples were analyzed, 9 were positive for amplification and 6 were obtained with its corresponding sequences. To alignment the sequences obtained, we used the BLAST database, giving us the 95% homology with the S. mutans UA159 genome. This study shows us the first evidence of Streptococcus mutans DNA sequence fragment recovered from dental caries and tartar from ancient human remains, presenting a 95% homology with S. mutans UA159 modern subspecies DNA
